Re: [PATCH 3/3] reset: socfpga: use readl/writel_relaxed

From	Arnd Bergmann <arnd@arndb.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3/3] reset: socfpga: use readl/writel_relaxed
Date	2016-07-05 13:20 +0200
Message-ID	<rRwyu-24B-21@gated-at.bofh.it> (permalink)
References	<rRvCq-1tJ-31@gated-at.bofh.it> <rRvCr-1tJ-51@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Tuesday, July 5, 2016 12:17:52 PM CEST Philipp Zabel wrote:
> This just removes the rmb()/wmb() pair between register read and
> write. Since no relevant reads follow the rmb and no relevant writes
> precede the wmb, they should be safe to remove.
> 
> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

We should only do this if you are fixing a bug (which you don't mention
in the changelog), or if you can show a relevant performance
improvement. Is this code ever used in a fast path? If it is,
wouldn't that indicate a problem in some driver?

	Arnd

Thread

[PATCH 1/3] reset: socfpga: no need to store modrst_offset Philipp Zabel <p.zabel@pengutronix.de> - 2016-07-05 12:20 +0200
  [PATCH 2/3] reset: sunxi: use readl/writel_relaxed Philipp Zabel <p.zabel@pengutronix.de> - 2016-07-05 12:20 +0200
  [PATCH 3/3] reset: socfpga: use readl/writel_relaxed Philipp Zabel <p.zabel@pengutronix.de> - 2016-07-05 12:20 +0200
    Re: [PATCH 3/3] reset: socfpga: use readl/writel_relaxed Arnd Bergmann <arnd@arndb.de> - 2016-07-05 13:20 +0200
      Re: [PATCH 3/3] reset: socfpga: use readl/writel_relaxed Philipp Zabel <p.zabel@pengutronix.de> - 2016-07-05 13:50 +0200
        Re: [PATCH 3/3] reset: socfpga: use readl/writel_relaxed Arnd Bergmann <arnd@arndb.de> - 2016-07-05 15:00 +0200
          Re: [PATCH 3/3] reset: socfpga: use readl/writel_relaxed Philipp Zabel <p.zabel@pengutronix.de> - 2016-07-05 15:30 +0200
  Re: [PATCH 1/3] reset: socfpga: no need to store modrst_offset Philipp Zabel <p.zabel@pengutronix.de> - 2016-07-06 18:30 +0200

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